The present invention relates to a walking aid apparatus which comprises a movable body for enabling the apparatus to move and a support unit for supporting a user to aid the user in walking.
As an apparatus for aiding old people and handicapped people with an impaired walking ability, there is a walking aid apparatus described in JP-A-2-5953, for example. JP-A-2-5953 discloses a walking aid apparatus which comprises a lower frame having a treading space for a user formed on the rear side, universal casters with braking mechanisms attached to the front and rear parts of both left and right sides of the lower frame, and an operation unit for operating the braking mechanisms. As the braking mechanism, JP-A-2-5953 discloses a brake in which when a lever of the operation unit is gripped with one hand, a drive piece arranged near the caster is pivoted about a pivot shaft to abut against the upper end of an actuating rod, pushing down the actuating rod, which in turn presses a braking piece, which has a friction surface for contact with a wheel, against the wheel to render the turning and traveling of the wheel impossible.
JP-A-5-329186 discloses a walking aid apparatus which comprises a movable body for aiding a user to walk, a support unit for supporting the weight of the user, and a detector for detecting a force acting in a direction in which the user is walking, wherein a detected value from the detector is compared with its target value to control the movement of the movable body. JP-A-5-329186 also discloses control means which comprises left and right setters for setting target force values, left and right comparators for comparing the target force values and the detected force values from the force detector, scale multipliers for amplifying differential values from these comparators; and adders for adding the amplified differential values from the scale multipliers and the target force values from the setters. JP-A-5-329186 describes that the use of this control means allows the user to push the walking aid apparatus with a constant force at all times regardless of the mass of the apparatus and an inclination of a road.
The walking aid apparatus described in JP-A-2-5953 is the one which is pushed only by the user himself. In such a push-type walking aid apparatus, when the user stumbles, he is likely to strongly push the apparatus forward and may be left behind.
In this case, although it is possible that the user may grip the lever on the operation unit to brake the apparatus by the manual braking mechanism, it may be difficult for the user, who is old or handicapped, to operate the brake. When the user stumbles or the apparatus is used on a slope, he or she may not be able to apply brake quick enough. This type of apparatus therefore demands improvement in terms of operability.
While some resistance may be applied to the wheels at all times to make the aid apparatus difficult to move and thereby eliminate the possibility of the user getting left behind, the user needs to push the apparatus with a stronger force at all times, which obviously makes the apparatus difficult to handle.
In a walking aid apparatus which performs the movement control based on the force applied to the apparatus from the user, like the one described in JP-A-5-329186, when the user stumbles and applies a strong push to the apparatus, the movement of the apparatus is controlled so that the apparatus moves greatly according to the strong force applied inadvertently by the user, with the result that the user may get left behind.
Further, in this walking aid apparatus, the user can push the apparatus on a horizontal or sloped surface with a desired constant force Uref by setting that force in the apparatus. When the force Uref set in the walking aid apparatus is set at xe2x80x9c0xe2x80x9d, it is possible to stop the walking aid apparatus even when the force applied to the apparatus on the sloped surface is rendered xe2x80x9c0xe2x80x9d, i.e., the user releases his hand from the apparatus.
However, the user may lean on the apparatus to reduce the burden on his legs or to keep his balance. In that case, the apparatus is applied with a force acting vertically and downwardly. If such a force is applied to the apparatus on the sloped surface, the force detector detects a force which is equivalent to one that tends to push the apparatus downwardly along the sloped surface. Hence, the apparatus is controlled to move down the sloped surface, so that the user may be left behind.
What is described above also applies to the case where the user is walking. When the user walks leaning on the apparatus, a vertically downward force acts on the apparatus which is then controlled to move down based on a force which is larger in magnitude than the user recognizes, so that the user may be left behind.
The conventional apparatuses, however, do not consider automatic application of brake regardless of the operation on the part of the user in the above-mentioned case. It is therefore an object of the present invention to provide a safe walking aid apparatus which prevents such a phenomenon that the apparatus moves or is performed the movement control with a force applied inadvertently to the apparatus by the user and thus the user is left behind.
To achieve the above object, a walking aid apparatus according to the present invention comprises a movable body and a support unit provided to the movable body, and further comprises means for reducing a change rate of a speed of the movable body with respect to a change in force acting on the support unit when the speed of the movable body increases.
A walking aid apparatus of the present invention comprises a movable body, a support unit provided to the movable body, and a controller for controlling movement of the movable body, and further comprises force detection means for detecting a force acting on the support unit, and control means for reducing, based on a detection result in the force detection means, a change rate of a speed of the movable body with respect to a change in force acting on the support unit when the speed of the movable body increases.
A walking aid apparatus of the present invention comprises a movable body and a support unit provided to the movable body, and further comprises resistance application means for increasing a resistance applied to the movable body when a speed of the movable body increases.
In these walking aid apparatus, it is more difficult to increase the speed of the apparatus when the moving speed is high than when the moving speed is low. Hence, even when the user stumbles and applies a strong force to the support unit, the movable body can be prevented from moving suddenly, thus minimizing the possibility of the user getting left behind the apparatus. When the apparatus is moving at slow speed, it can be moved easily with a small force, thus facilitating the handling.
Further, a walking aid apparatus of the present invention comprises a movable body, a support unit provided to the movable body, and a controller for controlling movement of the movable body, and further comprises control means for detecting a force acting on the support unit to control a change rate of an acceleration with respect to a change in the force, wherein the control means is adapted to make the change rate during acceleration smaller than that during the deceleration.
A walking aid apparatus of the present invention comprises a movable body, a support unit provided to the movable body, and a controller for controlling movement of the movable body based on a force applied to the movable body, wherein an absolute value of an acceleration when a force is applied in a direction in which the movable body is accelerated is made smaller than an absolute value of an acceleration when the same force is applied in a direction in which the movable body is decelerated.
In these walking aid apparatus, although the acceleration performance is set low to forestall a situation where the movable body is suddenly moved forward leaving the user behind, a high deceleration performance can be obtained. Therefore, even when the user stops suddenly for some reason, the apparatus can be stopped quickly, thus preventing the user from being left behind.
Furthermore, a walking aid apparatus of the present invention comprises a movable body, a support unit provided to the movable body, and a controller for controlling movement of the movable body based on a force applied to the movable body, and further comprises inclination angle detection means for detecting an inclination angle of the movable body, wherein a movement control of the movable body is corrected based on an output of the inclination angle detection means so as to eliminate an influence of a vertical component of a force applied to the movable body.
A walking aid apparatus of the present invention comprises a movable body, a support unit provided to the movable body, and a controller for controlling movement of the movable body based on a force applied to the movable body, wherein a movement control is performed so that even when a vertical force is applied to the movable body on a slope with no horizontal force applied, the movable body remains at its position.
On a slope, the longitudinal force components are produced by the vertical force applied to the movable body from the user, so that the movement control of the movable body is performed based on the longitudinal force components. Generally, the vertical force applied to the movable body from the user is not intended to move the apparatus. Thus, removing the influences of this component of force from the movement control of the movable body makes it possible to prevent unwanted movement of the movable body, thereby forestalling a situation where the user may get left behind the apparatus.
In the above apparatus, the force applied to the movable body from the user should be detected preferably by detecting with force detection means a force applied to the support unit from the user.
Furthermore, a walking aid apparatus of the present invention comprises a movable body, a support unit provided to the movable body, and a controller for controlling movement of the movable body, and further comprises means for stopping the movable body when the means detects that the movable body moves back and comes within a predetermined distance to an object.
In this walking aid apparatus, even when the user applies a backward force to the support unit unconsciously, the movable body can be stopped moving back before reaching the user.
As described above, the present invention can forestall a situation where the user may be left behind the walking aid apparatus.
In the foregoing description, the speed increase of the movable body means to increase the speed of the movable body either in the forward or backward direction.